People increasingly generate content on their personal endpoint devices, e.g., mobile devices, laptops, home computers, and the like, and upload the content to a third-party service for sharing and backup purposes. Although these services are convenient and useful, their use has important privacy implications due to their centralized nature and their acquisitions of rights to user-contributed content. For example, if a hacker maliciously attacks the third-party service, the hacker would obtain access to private information of all users that are signed up with the third-party service. In addition, when a user subscribes to a third-party service, they are typically required to sign an agreement that allows the third-party service to sell or share the user's private information. As a result, the user's privacy may be compromised or at risk.